libsdl-org
Hide some SDL structure
Adding or removing fields to structure are always api breakage.
Should we try to expose less SDL structures, so that they don't prevent to break api.
- doesn't make sense to hide SDL_rect, because all fields are used
- doesn't make sense to expose SDL_render, because almost no fields are used.
Candidate are structures, with few used fields, that can be hidden, and we add get/set function for usage
Tossing this into 3.0 ABI for further review, but it's possible that SDL_Properties mitigates this.
I grepped the codebase for lines with "typedef" and "struct", which brings up 125 items.
Most of these are already good (including the previously-mentioned SDL_Renderer, which is already an opaque type).
The only ones I saw that I think are worth considering at all...
- SDL_AtomicInt: maybe we just make this totally opaque, since its point is to prevent accessing the int value directly anyhow.
- SDL_Surface: Probably the perfect example of what @1bsyl is thinking of here, right?
- SDL_DisplayMode: has a
driverdatafield, which is a little awkward, maybe. - SDL_hid_device_info: I don't love that this is a linked list and has
unsigned shortvalues andwchar_t *fields, but I assume this is inherited from hidapi and we can't do much about this and most people don't need it anyhow.
The rest looks pretty good from here. A big pain point was SDL_RWops, but now it is opaque, and if we want to change the interface struct to add/remove/change function pointers, we'll just make a Version 2 struct and a new function to create an SDL_IOStream with the different interface, and paper over the Version 1 differences internally.
Anyhow, we can decide what to do with these (which might be nothing).
SDL_AtomicInt: maybe we just make this totally opaque, since its point is to prevent accessing the int value directly anyhow.
(then again, you can't simply create these as static/global if we make these opaque, which is a very common way to use atomic ints.)
I'm investigating trimming down SDL_Surface now, and opened a separate issue for SDL_DisplayMode in https://github.com/libsdl-org/SDL/issues/10198. SDL_AtomicInt we want to be static/global, and we won't touch SDL_hid_device_info, for source code compatibility with hidapi.